As a method for preparing granules in the field of powder production of pharmaceutical products, food products, and the like, a method of coating a core particle with a coating layer according to a layering method has been known.
The term “layering method” used herein refers to a method of coating a core particle with a coating layer, which comprises spraying a layering liquid containing an active ingredient such as a medicinal ingredient, a binder, and the like to a core particle.
Moreover, for purposes such as improvement in the stability of the active ingredient such as the medicinal ingredient, taste masking, means for controlling the dissolution of the active ingredient, and provision of enteric coating properties, a technique for film coating a granule produced using a core particle has been known.
A film-coated granule has been directly administered as a fine granule, or from the viewpoint of ease of handling, it has been placed into a capsule and then administered in many cases. In recent years, however, from the viewpoint of ease of consumption and reduction in cost, the development of, what is called, a granule-containing tablet, produced by compressing a film-coated granule and excipients, has been progressing. Among others, with the aging of population and changes in the living environment, an orally-disintegrating tablet, which can be easily consumed, while maintaining ease of handling that is characteristic of tablets, and which can be easily consumed at any time anywhere without water, has been under development.
By the way, as core particles used in the production of granules, the following core particles have been known, for example.
Patent Document 1 discloses a film coating method which comprises layering a medicinal ingredient to a sugar core particle and then film coating the thus obtained core particle. Patent Document 2 discloses a method of laminating a drug to microcrystalline cellulose used as a core particle and further film coating the core particle. In addition, Patent Document 3 describes a method for producing a spherical granule containing 20% or more of fine microcrystalline cellulose, which is used as a coated granule. Moreover, Patent Document 4 discloses a pharmaceutically inactive spherical core containing 50% or more of microcrystalline cellulose having a mean degree of polymerization of from 60 to 375, and a film coating method comprising layering a drug to the spherical core. Furthermore, Patent Document 5 discloses: a cellulose pharmaceutical particle obtained by mechanically crushing cellulose to obtain microcrystalline cellulose, preparing a dispersion of the microcrystalline cellulose, converting the dispersion to the form of liquid droplets, and drying the droplets; and a film coating method, which comprises laminating medicinal ingredients to the thus obtained particles. Still further, Patent Document 6 discloses a spherical core containing 0% to 95% by weight of microcrystalline cellulose and 5% to 100% by weight of trehalose.
Patent Document 1: Japanese Patent Laid-Open No. 61-1614
Patent Document 2: Japanese Patent Laid-Open No. 2000-109426
Patent Document 3: Japanese Patent Publication No. 7-2761
Patent Document 4: Japanese Patent No. 2542122
Patent Document 5: International Publication No. WO02/36168
Patent Document 6: Japanese Patent Laid-Open No. 2001-172430